1. Field of the Invention
The present invention relates to a position detector capable of absolutely detecting any of a large number of positions spaced, for example, circumferentially of a rotary element, without returning to an origin or a starting point.
2. Description of the Prior Art
Conventionally, magnetic encoders or optical encoders are in wide practical use as encoders for detecting an absolute position on a rotary element such as, for example, a robot hand. In particular, optical encoders employing binary codes can detect the absolute position with superior responsibility and reliability.
In the binary codes, however, since a row of codes merely provide position data of one bit, an encoder having a high resolution needs plural rows of codes corresponding to the number of bits required, light emitting and light receiving elements corresponding thereto, and an amplifier unit or units. As a result, there arises a problem in that the encoder becomes expensive because the number of parts increases and adjustments thereof are troublesome and time-consuming.